Find out the standard SAP menu you would like to extend. Standard SAP main menu is “S000”, you can display this menu using SE43 and go to the node you are interested and click on “Goto -> Attributes” to find out the menu under which this node exists.
Go to transaction SE43 and enter the standard SAP menu you would like extend and click on change
In the subsequent popup window select Extend, failure to select this will result will result in modification to standard SAP and you will loose your extensions during upgrade/patches
If you don’t have an enhancement ID (Similar to CMOD project) for this, create one by clicking on Create in the popup window. If you already have one, double click on the enhancement ID. This will assign all the additions to the menu to enhancement ID and are protected during the upgrades and patches. If you get any information message on repairs, click continue
Add your menu to the SAP standard menu as displayed on the screen. Here you can either add your own menu or just add the transaction code directly